scholarly journals Preparation and Anti-frost Performance of PDMS-SiO2/SS Superhydrophobic Coating

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1051
Author(s):  
Li Jia ◽  
Jun Sun ◽  
Xiaoxiao Li ◽  
Xian Zhang ◽  
Lin Chen ◽  
...  
Keyword(s):  
Hybrid Coating ◽  
Process Time ◽  
Superhydrophobic Coating ◽  
Hydrophobic Group ◽  
Water Contact ◽  
Organic Silicon ◽  
Maximum Water ◽  
Coated Surface ◽  
Silicon Sol ◽  
Frost Layer

Polydimethylsiloxane modified SiO2/organic silicon sol (PDMS-SiO2/SS) hybrid coating was synthesized via a simple two-step modification route. The nanoparticles (NPs) of PDMS-SiO2 were synthesized through a high temperature dehydration reaction by using silica and excessive PDMS. The NPs lapped with each other and formed a branch and tendril structure. Organic silicon sol (SS) added as basement introduced a hydrophobic group and protected the structure of the NPs. The PDMS-SiO2/SS hybrid coating exhibits a superhydrophobic performance with a maximum water contact angle of 152.82°. The frost test was carried out on a refrigerator evaporator, and the results showed that the coating did not merely delay the frost crystal time about 113 min but also increased the frost layer process time. Meanwhile, the defrosted water droplets rolled off from the coated surface easily which is a benefit for frost suppression performance of the next refrigeration cycle.

scholarly journals Fabrication of superhydrophobic composite coating based on fluorosilicone resin and silica nanoparticles

2018 ◽  
Vol 5 (7) ◽  
pp. 180598 ◽  
Author(s):  
Xiaoming Wang ◽  
Xingeng Li ◽  
Qingquan Lei ◽  
Yaping Wu ◽  
Wenjing Li
Keyword(s):  
Silica Nanoparticles ◽  
Composite Coating ◽  
Room Temperature ◽  
Silica Content ◽  
Superhydrophobic Coating ◽  
Polymer Model ◽  
Modified Silica ◽  
Sliding Angle ◽  
Water Contact ◽  
Modified Silica Nanoparticles

Composite superhydrophobic coating built with film former and filler is attracting much attention for its facile and convenient fabrication, but significant limitations and disadvantages still remain. In this paper, a composite superhydrophobic coating is introduced which can be cured at room temperature and made by dispersing modified silica nanoparticles with 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane in fluorosilicone resin. Silica content and dispersion time showed obvious influences on the morphology and topography of composite coating by reuniting dispersed nanoparticles to form peaks on the surface. Excessively large distances between these peaks would decrease water contact angle value. Increasing slope of peaks, appropriate distance between peaks and decreasing diameter size of peaks would diminish sliding angle value. Formation mechanism of the composite coating based on fluorosilicone resin and modified nanoparticles was explained using interpenetrating polymer model.

scholarly journals Superhydrophobic Coatings as Anti-Icing Systems for Small Aircraft

Aerospace ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 2 ◽  
Author(s):  
Filomena Piscitelli ◽  
Antonio Chiariello ◽  
Dariusz Dabkowski ◽  
Gianluca Corraro ◽  
Francesco Marra ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Work Of Adhesion ◽  
Ice Formation ◽  
Superhydrophobic Coating ◽  
Additional Energy ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Promising Solution ◽  
Reference Samples ◽  
Small Aircraft

Traditional anti-icing/de-icing systems, i.e., thermal and pneumatic, in most cases require a power consumption not always allowable in small aircraft. Therefore, the use of passive systems, able to delay the ice formation, or reduce the ice adhesion strength once formed, with no additional energy consumption, can be considered as the most promising solution to solve the problem of the ice formation, most of all, for small aircraft. In some cases, the combination of a traditional icing protection system (electrical, pneumatic, and thermal) and the passive coatings can be considered as a strategic instrument to reduce the energy consumption. The effort of the present work was to develop a superhydrophobic coating, able to reduce the surface free energy (SFE) and the work of adhesion (WA) of substrates, by a simplified and non-expensive method. The developed coating, applied as a common paint with an aerograph, is able to reduce the SFE of substrates by 99% and the WA by 94%. The effects of both chemistry and surface morphology on the wettability of surfaces were also studied. In the reference samples, the higher the roughness, the lower the SFE and the WA. In coated samples with roughness ranging from 0.4 and 3 µm no relevant variations in water contact angle, nor in SFE and WA were observed.

scholarly journals Effect of TiO2 Powder on the Surface Morphology of Micro/Nanoporous Structured Hydrophobic Fluoropolymer Based Composite Material

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Bichitra Nanda Sahoo ◽  
Balasubramanian Kandasubramanian ◽  
Amrutha Thomas
Keyword(s):  
Phase Separation ◽  
Surface Morphology ◽  
Polymer Composite ◽  
Polyvinylidene Fluoride ◽  
Industrial Applications ◽  
Nanoporous Structure ◽  
Hydrophobic Surfaces ◽  
Water Contact ◽  
Maximum Water ◽  
The Impact

The present work reports a simple and effective way to produce hydrophobic foams with polyvinylidene fluoride (PVDF) and TiO2 by using a phase separation technique. This method involved the phase separation during the deposition of PVDF from its DMF solution with nonsolvent water in the presence of TiO2. The surface morphology of hydrophobic surfaces was characterized by Field Emission Scanning Electron Microscope (FESEM). The maximum water contact angle of 129° was observed. The results confirm that the surface texture of polymer composite exhibits mixture of microporous and nanoporous structure. The impact of TiO2 on the wettability property of polymer composite has been studied. The proposed methodology might find applications in the preparation of hydrophobic surfaces for industrial applications.

scholarly journals Improving the Hydrophobicity of ZnO by PTFE Incorporation

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Meenu Srivastava ◽  
Bharathi Bai J. Basu ◽  
K. S. Rajam
Keyword(s):  
Thermal Treatment ◽  
Stearic Acid ◽  
Superhydrophobic Surface ◽  
Cost Effective ◽  
Electrical Energy ◽  
High Water ◽  
Superhydrophobic Coating ◽  
Water Contact ◽  
Low Surface Energy ◽  
Effective Manner

The objective of the present study is to obtain a zinc oxide- (ZnO-) based superhydrophobic surface in a simple and cost-effective manner. Chemical immersion deposition being simple and economical has been adopted to develop modified ZnO coating on glass substrate. Several modifications of ZnO like treatment with alkanoic acid (stearic acid) and fluoroalkylsilane to tune the surface wettability (hydrophobicity) were attempted. The effect of thermal treatment on the hydrophobic performance was also studied. It was observed that thermal treatment at 70°C for 16 hrs followed by immersion in stearic acid resulted in high water contact angle (WCA), that is, a superhydrophobic surface. Thus, a modified ZnO superhydrophobic surface involves the consumption of large amount of electrical energy and time. Hence, the alternate involved the incorporation of low surface energy fluoropolymer polytetrafluoroethylene (PTFE) in the ZnO coating. The immersion deposited ZnO-PTFE composite coating on modification with either stearic acid or fluoroalkylsilane resulted in a better superhydrophobic surface. The coatings were characterized using Scanning Electron Microscope (SEM) for the surface morphology. It was found that microstructure of the coating was influenced by the additives employed. A flower-like morphology comprising of needle-like structure arranged in a radial manner was exhibited by the superhydrophobic coating.

scholarly journals A Durable PVDF/PFOTES-SiO2 Superhydrophobic Coating on AZ31B Mg Alloy with Enhanced Abrasion Resistance Performance and Anti-Corrosion Properties

2021 ◽  
Vol 11 (23) ◽  
pp. 11172
Author(s):  
Zhiqiang Qian ◽  
Zhong Liu ◽  
Shidong Wang ◽  
XiuShen Ye ◽  
Zhijian Wu
Keyword(s):  
Contact Angle ◽  
Wear Resistance ◽  
Salt Spray ◽  
Mg Alloy ◽  
Superhydrophobic Coating ◽  
Friction Test ◽  
Sliding Angle ◽  
Sio2 Coating ◽  
Corrosion Properties ◽  
Water Contact

A simple and practical spray method is employed to prepare a PVDF/PFOTES-SiO2 superhydrophobic composite coating on the AZ31B Mg alloy substrate. The morphology, composition, and water contact angle (CA) were measured by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM) and contact angle measuring instrument. Hydrophilic nano-SiO2 is modified by PFOTES to obtain hydrophobicity. The influence of the mass of PFOTES-SiO2 to PVDF on the hydrophobic properties was studied. The wear resistance and stability of the composite coating have been investigated by immersion test, cross-cut adhesion test and friction test. Additionally, the corrosion resistance was measured by electrochemical workstation and salt spray corrosion test. The CA of PVDF/PFOTES-SiO2 coating is 161.3° and the sliding angle (SAs) is less than 2°. After 10× the sandpaper friction test, the superhydrophobic contact angle of the coating remained above 155°, and the sliding angle was less than 5°, which indicated that the prepared coating is a strong superhydrophobic coating with good wear resistance. The results of the electrochemical tests show that the superhydrophobic coating improved the anti-corrosion performance of Mg alloy, and the water contact angle is greater than 150° after 168 h salt spray corrosion test. Due to its excellent superhydrophobicity, wear resistance and anti-corrosion properties, the robust PVDF/PFOTES-SiO2 coating is considered to have great potential for future applications in the automotive and marine industries.

Sol-Gel Preparation of Optically Transparent Hydrophobic Hybrid Coating

2011 ◽  
Vol 391-392 ◽  
pp. 505-510
Author(s):  
Yan Pang ◽  
Yao Chen ◽  
Qi Qiu ◽  
Fang Wang ◽  
Zhang Tao
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Sol Gel ◽  
Weight Ratio ◽  
Hybrid Coating ◽  
Molar Ratio ◽  
Water Contact ◽  
Glass Slides ◽  
Optically Transparent ◽  
Gel Preparation

Optically transparent hydrophobic inorganic-organic hybrid sols was obtained employing Tetraethylorthosilicate (TEOS), Methyltriethoxysilane (MTES), and Heptadecafluoro-1, 1, 2, 2-tetradecyl)trimethoxysilane (FAS), with nitric acid as catalyst. Hybrid coating was dip coated on glass slides. The results showed that the water contact angle of MTES modified SiO2 coating was only 105° . As the weight ratio FAS varied from 0 to 8 wt.%, the water contact angle reached as high as 116.5°. The coated glass presented transmittance of 92%, 2% higher than the non-coated ones. The increase in transmittance suggested an antireflective effect of the hybrid coating. With further SEM characterization of the surface morphology, we finally obtained the optimized optically transparent hydrophobic hybrid coating with the MTES/TEOS_as 1/1(molar ratio) and FAS as 2 wt.%.

scholarly journals The improvement of gamma irradiation resistance of superhydrophobic coating with MWCNTs

2018 ◽  
Vol 175 ◽  
pp. 01014
Author(s):  
Jing Zhang ◽  
Yan Zhang ◽  
Yujian Liu
Keyword(s):  
Gamma Irradiation ◽  
High Dose ◽  
Superhydrophobic Coating ◽  
Water Contact ◽  
Multi Walled Carbon Nanotubes ◽  
Self Cleaning ◽  
Excellent Adhesion ◽  
Water Repellence ◽  
Walled Carbon Nanotubes ◽  
Irradiation Resistance

A superhydrophobic coating with excellent water repellence and gamma irradiation resistance was obtained by multi-walled carbon nanotubes (MWCNTs) modification. The effects of MWCNTs on the mechanical behaviour, water contact angle (WCA) and self-cleaning properties of the coatings were investigated. After 1.23×107 rad dose of gamma irradiation, WCA of the coating without MWCNTs modification (EPPM0) decreases from 150° to 140° and the adhesion reduces from 5B to 4B, respectively. While the coating (EPPM3) with 3wt% MWCNTs modification remains high WCA (152°), excellent adhesion (5B) and hardness (6H). The results of dust removal test suggest that the coating still maintains self-cleaning property after high dose gamma irradiation.

scholarly journals Cerium Stearate Electrodeposited Superhydrophobic Coatings for Active Corrosion Protection of Anodized AA 2024-T3

CORROSION ◽  
10.5006/3799 ◽  
2021 ◽  
Author(s):  
Abirami S ◽  
Bharathidasan T ◽  
Sathiyanarayanan Sadagopan ◽  
Arunchandran Chenan
Keyword(s):  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Industrial Applications ◽  
Environmental Stability ◽  
Process Time ◽  
Self Healing ◽  
Water Contact ◽  
Electrodeposition Time ◽  
Aa 2024 ◽  
Active Corrosion

The present study investigated the active corrosion protection provided by superhydrophobic cerium stearate coatings. Superhydrophobic cerium stearate was deposited on anodized AA 2024-T3 at 40 V with different electrodeposition times using a simple DC electrodeposition technique to know the role of electrodeposition time on surface morphology, hydrophobicity, and corrosion resistance. We characterized the structure and morphology of cerium stearate to understand its formation mechanism. Electrodeposition process at 40 V for 120 min resulted in the formation of dual scale Allium giganteum like micro/nano hierarchical texture of cerium stearate with a water contact angle (WCA) of 165 ± 1.6°. The cerium stearate coating obtained for 120 min process time had excellent self-cleaning property and good chemical stability, environmental stability, and mechanical durability acceptable for industrial applications. Electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET) were used to investigate the active corrosion protection of cerium stearate coating. The electrodeposited cerium stearate coating showed active corrosion protection based on self-healing ability by releasing cerium (Ce3+) ions.

scholarly journals Effects of Two-Step Anodization on Surface Wettability in Surface Treatment of Aluminum Alloy

2021 ◽  
Vol 59 (2) ◽  
pp. 73-80
Author(s):  
Jae Dong Eo ◽  
Jingyu Kim ◽  
Yongsug Jung ◽  
Jong-Hang Lee ◽  
Wook Bae Kim
Keyword(s):  
Academic Research ◽  
Contact Angles ◽  
Process Time ◽  
Process Conditions ◽  
Processing Conditions ◽  
Water Contact ◽  
Aluminum Oxides ◽  
Industrial Processing ◽  
Porous Aluminum ◽  
Aesthetic Appearance

Industrial anodizing of aluminum alloys is widely employed for various products, to improve corrosion and contamination protection as well as aesthetic appearance. At the same time, nanostructure fabrication using highly ordered porous aluminum oxides has been increasingly investigated in academic research for diverse micro-/nano applications. This approach is based on two-step anodization with limited process conditions, such as extended process time and low temperature. In this study, two-step anodizing was employed to anodize hairline-finished Al 1050 with sulfuric acid considering industrial processing conditions. The method is particularly suited for anodized products that require post-processing such as printing, dyeing and/or bonding. Porous anodized layers that were fabricated using conventional single anodizing, and twostep anodizing under identical processing conditions were compared. Variations in porosity, pore diameter, and inter-pore distance were examined in relation to the anodizing parameters, such as temperature and voltage. The results showed that two-step anodizing caused an increase in all measured pore-related measurements, and produced a much more uniform porous layer than the conventional anodizing process. Water contact angles were evaluated on the anodized surface of the previously machined hairline specimen. It was found that the water contact angles clearly decreased on the surfaces treated by two-step anodization, compared to the conventional anodizing process.

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